Why was the discovery of the archaeopteryx specimen so controversial?

Charles Darwin published his groundbreaking work on evolution, The Origin Of Species, in 1859. This book suggested that all animals and plants were related to each other by descent through a series of common ancestors, igniting furious debates over our understanding of the natural world. One of the key ideas proposed by Darwin was that it should be possible to find animals or plants that formed continuous evolutionary chains, showing how one species could be transformed into another. However, good examples of the links in these chains were difficult to find and Darwin’s opponents attacked this as a weakness in his theory.

By chance, in 1861, a spectacular fossil emerged from the late-Jurassic limestones of Germany and came to Darwin’s defence. This fossil, named archaeopteryx lithographica, was the earliest-known bird – easily recognised as such by the fossilised impressions of features surrounding its delicate skeleton. Crucially, although archaeopteryx was clearly a bird, it also displayed other features not found in living birds, but found in reptiles. These included tiny teeth in the bones of the beak and a long bony tail. It instantly became an example of a ‘missing link’, providing evidence for the evolution of birds from reptiles, vital support for Darwin’s new idea.